Scheduled airline carriers, as distinct from charter operators, offer three classes of seating, namely first, business and economy.
In order to maximise profitability scheduled airline operators arrange the seating in the aircraft based on predicted load factors, as between these three classes. Business class accommodation is recognized by all major carriers as the highest profit earner, and therefore the need arises for a high degree of flexibility as regards the provision of the number of business class seats to be provided on any particular route, because demand for such seats depends to a large extent on the route taken. For example, demand for business class accommodation on the London to New York run is high while that between London and Bombay for instance is normally low.